RADIONUCLIDE ASSESSMENT OF CARDIOPROTECTIVE EFFICIENCY OF HYPOXIC PRECONDITIONING
Zh.V. Vesnina, Cardiology Research Institute, Tomsk Nationale Research Medical Centre, N.G. Krivonogov, Yu.A. Arsenjeva, E.A. Nesterov, Yu.B. Lishmanov, Cardiology Research Institute, Tomsk Nationale Research Medical Centre, Cardiology Research Institute, Tomsk Nationale Research Medical Centre, Tomsk National Research Polytechnic University, Cardiology Research Institute, Tomsk Nationale Research Medical Centre
Russian Electronic Journal of Radiology
Using radiocardiopulmonography to evaluate the cardioprotective effectiveness of hypoxic preconditioning (HP) during myocardial revascularization under extracorporeal circulation (EC). Material and methods. A total of 63 patients (mean age of 52.8 ± 1.4 years) who underwent coronary bypass surgery (CABG) under EC condition were examined. All patients had chronic heart failure of NYHA class I-III. Patients were randomized into 2 groups: study group comprised 33 patients who received HP during
... G; comparison group comprised 30 patients. Patients of both groups were comparable in regard to clinical and intraoperative data. The preconditioning was performed as a single-cycle 10-minute hypoxemia session followed by 5-min period of reoxygenation before global ischemia. Radiocardiopulmonography with 99mТс-pertechnetate was performed before and 6-8 days after surgery with the calculation of the parameters of cardiopulmonary hemodynamics. Results. In the examined patients before CABG we observed a decrease in the mean values of the cardiac output (MO), cardiac index (HI), stroke index (SI) and circulation efficiency ratio (CER) as a consequence of a decrease in the pumping function of the heart, as well as an increase in the pulmonary circulation time (TPUL) due to both arterial and venous components, which indicated the development of pulmonary hypertension and venous congestion of the left heart. In the postoperative period, positive statistically significant change in most parameters of cardiopulmonary hemodynamics occurred as a result of successful myocardial revascularization in patients of both groups: the values of MO, SI, CER increased, and halfemptying period of the left and right ventricles and the value of TPUL decreased. It should be noted that the positive dynamics of these parameters was statistically more pronounced in the patients of the study group. Also, in contrast to the comparison group, the arterial component of circulation in the lungs and the half-emptying period of the right ventricle significantly decreased in patients with HP, which indicated a reduction in pulmonary hypertension and a regression of right ventricular failure. On day 2 after surgery blood levels of creatine-kinase (CK) and CK-MB were increased in patients of both groups. The mean level of CK-MB was significantly higher (by 33%) in the comparison group relative to the study group (p = 0.046825), and the relative index (RI = CK-MB/CK x 100) in the study group did not exceed 6%. This data suggested that HP increased the tolerance of the heart to the effects of "ischemia-reperfusion". Conclusion. Hypoxic preconditioning exerted cardioprotective activity in patients undergoing open-heart surgery under EC.